Ana Márcia Macedo Ladeira Carvalho

Quality of Wood and Charcoal from Eucalyptus Clones for Ironmaster Use

Considering the wide variety of species and clones of Eucalyptus cultivated in Brazil, it is necessary to search for new information on wood properties, so that the selection of genetically superior material may be successful. The present study aimed to determine the properties of wood and charcoal from different clones of Eucalyptus spp. Six clones at the age of 7.5 years were evaluated and the samples were from a clonal, located in the city of Lassance, Minas Gerais, Brazil. Basic density, chemical composition, and higher heating value were determined. Carbonizations in a laboratory kiln were done and the levels of volatile matter, ash, and fixed carbon, higher heating value, and bulk density of the charcoal produced were determined. Evaluated genetic materials showed differences in their properties. According to research results, several properties of wood should be considered together for the selection of clones for charcoal production. However, basic density and chemical composition of wood, especially high contents of lignin and low contents of extractives, are the properties that had more influence on charcoal yield and its quality. Concerning charcoal production for steelmaking, clone 6 stood out and, conversely, clone 4 showed inferior properties to those of others.

Propriedades de chapas tipo OSB, fabricadas com partículas acetiladas de madeiras de Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus cloeziana e Pinus elliottii

The objectives of this work was to evaluate the properties of OSB (Oriented Strand Board). Wood was collected from Eucalyptus grandis, Eucalyptus urophylla and Eucalyptus cloeziana on the municipalities of Ponte Alta and Tres Marias, in the state of Minas Gerais. Wood densities were respectively: Ponte Alta (0.55, 0.61 and 0.70g/cm³) and Tres Marias (0.56, 0.58 e 0.69g/cm³). Strands of Pinus elliottii, derived from the city of Vicosa, with density of 0.45g/cm³, were added to strands of eucalyptus when necessary to keep board densities close to 0.70g/cm³. Flakes were fabricated in a laboratory disk flaker measuring approximately 20.00 x 0.46 x 90.00 mm. Phenol-formaldehyde adhesive was applied at 8% solid rate, in relation to particle dry mass. Part of the treatment was carried out with flakes from acetylated eucalyptus. The boards were pressed at 170°C and 32 kgf/cm² pressure. Boards properties were determined according to the ABNT NBR 14810-3 (2002) and ASTM-D 1037 (1991) norms. The results were compared using the ANSI/A - 208.1 (1993) and CSA 0437-93 (1993) norms. OSB manufactured with any amount of acetylated flakes was more stable and absorbed less water. However the resistance to perpendicular traction of OSB with 100% of acetylated flakes was inferior to the stipulated by the CSA O437-0/93 (1993) norm. It was also found that acetylation had a negative effect on screw withdrawal resistance, module of rupture (parallel and perpendicular) and longitudinal compression resistance (perpendicular) of Eucalyptus grandis OSB having 100% of their flakes acetylated. Boards that presented numerically the highest means were manufactured with non-acetylated flakes of Eucalyptus grandis (Janka hardness) and Eucalyptus cloeziana mixed with Pinus sp (module of rupture). Only resistance to longitudinal compression was affected by the wood origin. OSB manufactured with Eucalyptus urophylla wood, from the Cerrado, had lower means than OSB made of the same species, however, from Vale do Rio Doce.

The effect of reaction wood on bleached eucalypt kraft pulp production - Part I

Wood quality is the key element for the production of high-performance, high-bleachability cellulose pulp. The presence of reaction wood may have significant impact on its various applications. This study investigated the effect of reaction wood on the production of bleached eucalypt kraft pulp. Normal and reaction wood eucalypt chips were compared regarding their indepth chemical composition and kraft pulping. The Kraft pulps derived from normal and reaction wood were compared for bleachability, chemistry and quality. Reaction wood requires less effective alkali to reach a given delignification degree, but retains less yield in relation to normal wood. At the kappa number 18±0.5, the brown pulp derived from reaction wood contains less cellulose and hemicelluloses, more HexA and lower viscosity in relation to that of normal wood. Although the pulp derived from reaction wood showed slightly lower efficiency in the oxygen delignification stage it performed better across ECF bleaching, reaching a brightness 1% higher at fixed chemical charge. The final bleached pulp derived from reaction wood showed lower viscosity and higher brightness reversion in relation to normal wood. Thus, reaction wood chips can be used for production of bleached grade pulps without major concern, if combined in small fractions to normal wood. ADDRESSES OF THE AUTHORS: Walter Torezani Neto Boschetti (walterboschetti@gmail.com), Jorge Luiz Colodette (colodett@ufv.br), Ana Márcia Macedo L. Carvalho (ana.marcia@ufv.br), Robsnéia Adriana Ribeiro (adrianaribeiro_qui@yahoo.com.br), Diego Pierre de Almeida (adpdiego@yahoo.com.br), and Carolina Marangon Jardim (cmjardim@gmail.com), Federal University of Viçosa, Department of Forest Engineering, Viçosa, Brasil. Corresponding author: Walter Torezani N. Boschetti

The effect of reaction wood on the properties of eucalyptus kraft pulp - Part II

The fibers of Eucalyptus wood have characteristics relevant to the Brazilian pulp industry in the production of tissue papers, printing and writing papers, and more recently paper for packaging. The chemical composition and morphology of the fibers of reaction wood are distinct from normal fibers, and can influence both the pulping parameters and the paper properties. The objective of this study was to evaluate the quality of bleached Eucalyptus Kraft pulp, from reaction wood, on paper production. For that, the physicalmechanical and optical properties of bleached eucalyptus pulps produced from trees with straight stem and inclined stem, normal and reaction wood, respectively, were analyzed. The reaction pulp presented physical, mechanical and optical properties superior to the normal pulp, with the exception of tear resistance and apparent specific volume. As such, the reaction pulp obtained higher potential for paper production than the normal pulp. For sanitary purposes, the reaction pulp achieved good water absorption results and also reduced the energy consumption during refining, despite a slight decrease in the tensile and tear index. For the production of printing and writing papers, the reaction pulp had better performance in the optical mechanical resistance properties, with the exception of tear resistance. ADDRESSES OF THE AUTHORS: Walter Torezani Neto Boschetti (walterboschetti@gmail.com), Rubens Chaves de Oliveira (rchaves@ufv.br), and Ana Márcia Macedo Ladeira Carvalho (ana.marcia@ufv.br), Federal University of Viçosa, Department of Forest Engineering, Viçosa, Brasil; Maria Fernanda Vieira Rocha (mfvrocha@yahoo.com.br), Federal University of Lavras, Department of Forestry Sciences, Lavras, Brasil. Corresponding author: Walter Torezani N. Boschetti